350-601 Network Practice Test 11 — 15 Questions

Question 1

In a VXLAN EVPN fabric using BGP as the control plane, which BGP address family is used to exchange MAC/VTEP reachability information between VTEPs?

Accepted Answer

L2VPN EVPN. In a VXLAN EVPN fabric, the L2VPN EVPN address family (AFI 25, SAFI 70) is used to exchange MAC/VTEP reachability information between VTEPs. This address family carries BGP EVPN routes (type-2 for MAC/IP advertisements) that include the MAC address, VNI, and VTEP IP, enabling the control plane to distribute host reachability without flooding.

Answer

IPv4 unicast

Answer

IPv6 unicast

Answer

VPNv4 unicast

Question 2

A data center architect is designing a spine-leaf network with 40 leaf switches and 4 spine switches. Each leaf has 48 x 25G server-facing ports and 8 x 100G uplinks to the spines. What is the oversubscription ratio from server to spine?

Accepted Answer

1.5:1. The oversubscription ratio is calculated by comparing the total server-facing bandwidth to the total uplink bandwidth. Each leaf switch has 48 x 25G server ports = 1200 Gbps of server-facing capacity, and 8 x 100G uplinks = 800 Gbps of spine-facing capacity. The ratio is 1200:800, which simplifies to 1.5:1, meaning the server-facing side has 1.5 times the bandwidth of the uplinks.

Answer

2:1

Answer

3:1

Answer

4:1

Question 3

Which NX-OS command displays the current VLAN configuration on a Nexus switch?

Accepted Answer

show vlan. The 'show vlan' command on NX-OS displays the current VLAN configuration, including VLAN IDs, names, status, and ports assigned to each VLAN. This command is the standard way to view VLAN information in Cisco NX-OS, similar to IOS, and it shows both default and user-created VLANs.

Answer

show running-config vlan

Answer

show vlan brief

Answer

show interface vlan

Question 4

In a Cisco ACI fabric, an external L3Out is configured to advertise a subnet to the outside. Which object must be created in the tenant to define the Layer 3 outside network connection?

Accepted Answer

L3Out. In Cisco ACI, an L3Out is the object that defines the Layer 3 outside network connection for a tenant. It is created within the tenant to specify the routing protocol (e.g., OSPF, BGP, EIGRP) and the external subnet that will be advertised to the outside world. Without an L3Out, the fabric cannot establish external connectivity or advertise routes.

Answer

External EPG

Answer

Contract

Answer

Bridge Domain

Question 5

An engineer notices that a vPC peer link is flapping. Which vPC component must be operational for the vPC to function correctly?

Accepted Answer

vPC peer link. The vPC peer link is the critical component that must be operational for the vPC to function correctly. It carries control-plane traffic (e.g., Cisco Fabric Services over Ethernet, or CFSoE) and data-plane traffic between the two vPC peer switches. If the peer link flaps, the vPC domain cannot synchronize the necessary state information, causing the vPC to fail or become unstable.

Answer

vPC member port

Answer

vPC consistency check

Answer

vPC peer keepalive link

Question 6

Which VLAN range is reserved by default on Cisco Nexus switches?

Accepted Answer

VLAN 1. VLAN 1 is the default VLAN on Cisco Nexus switches and cannot be deleted or renamed. It is automatically created on all switches and carries all untagged traffic by default, making it a reserved VLAN that is always present in the VLAN database.

Answer

VLAN 1002-1005

Answer

VLAN 3968-4047

Answer

VLAN 4094

Question 7

In a VXLAN overlay, which encapsulation is used to transport Ethernet frames over the IP network?

Accepted Answer

UDP. VXLAN uses UDP encapsulation (destination port 4789 by default) to transport Layer 2 Ethernet frames over a Layer 3 IP network. This allows the overlay to leverage existing IP routing infrastructure while preserving the original MAC addresses and VLAN information, enabling network virtualization and scalability beyond traditional VLAN limits.

Answer

IPsec

Answer

TCP

Answer

GRE

Question 8

A network engineer is configuring an ACI contract between an EPG and an external EPG. Which construct is used to permit traffic from the external EPG to the internal EPG?

Accepted Answer

The external EPG is the provider and the internal EPG is the consumer.. In Cisco ACI, the provider EPG exposes a contract, and the consumer EPG consumes it. To permit traffic from an external EPG to an internal EPG, the internal EPG must be the consumer (initiating the communication) and the external EPG must be the provider (offering the contract). This aligns with the default directionality of contracts, where the provider's filter rules allow inbound traffic from the consumer.

Answer

The internal EPG is the provider and the external EPG is the consumer.

Answer

Both EPGs are providers.

Answer

Both EPGs are consumers.

Question 9

Which feature in NX-OS allows for direct API calls to the switch for automation purposes?

Accepted Answer

NX-API. NX-API (option A) is the correct answer because it is the native NX-OS feature that exposes a RESTful API interface, allowing direct HTTP/HTTPS calls (e.g., GET, POST, PUT, DELETE) to the switch for automation and programmability. This enables tools like Ansible, Postman, or custom scripts to send structured data (JSON/XML) to configure, monitor, and manage the switch without requiring CLI parsing or SSH sessions.

Answer

Python scripting

Answer

Bash shell

Answer

SNMP

Question 10

In a spine-leaf architecture, what is the primary advantage of having multiple spine switches?

Accepted Answer

Redundancy and load balancing. In a spine-leaf architecture, multiple spine switches provide redundancy by ensuring that if one spine fails, traffic can still flow through other spines. They also enable load balancing because leaf switches can use equal-cost multipath (ECMP) routing to distribute traffic across all available spine uplinks, maximizing bandwidth utilization and preventing congestion on any single path.

Answer

Lower latency

Answer

Simplified management

Answer

Increased oversubscription

Question 11

Which two statements correctly describe VXLAN BUM traffic handling? (Choose two.)

Accepted Answer

Ingress replication sends unicast copies of the BUM traffic to each remote VTEP.. In VXLAN, BUM traffic (Broadcast, Unknown unicast, Multicast) can be handled using ingress replication, where the ingress VTEP creates multiple unicast copies of the packet and sends them directly to each remote VTEP. This is the default mode in many VXLAN implementations, especially in EVPN-based fabrics, and does not require a multicast group in the underlay. Option A correctly describes this behavior.

Answer

BUM traffic is dropped by default.

Answer

Ingress replication sends a single multicast packet to all VTEPs.

Answer

Multicast is required for VXLAN BUM handling.

Question 12

Which two BGP features are commonly used in a Cisco Data Center spine-leaf fabric to achieve optimal ECMP load balancing? (Choose two.)

Accepted Answer

BGP add-path. BGP add-path (A) allows the advertisement of multiple paths for the same prefix to a peer, enabling the spine to install multiple equal-cost paths in its routing table for ECMP load balancing. BGP multipath (C) instructs the router to install multiple equal-cost BGP paths into the routing table, which is essential for distributing traffic across multiple spine links in a Clos fabric.

Answer

BGP confederation

Answer

BGP next-hop-self

Answer

BGP bestpath tie-break

Question 13

In a spine-leaf data center architecture, what is the primary purpose of using equal-cost multipath (ECMP) routing?

Accepted Answer

To provide load balancing across multiple paths between leaf and spine switches. In a spine-leaf architecture, ECMP is used to distribute traffic across multiple equal-cost paths between leaf and spine switches. This provides load balancing by hashing flows across available uplinks, maximizing bandwidth utilization and ensuring no single link is overwhelmed. ECMP is a Layer 3 routing feature that operates with protocols like OSPF or BGP, not a Layer 2 or encapsulation mechanism.

Answer

To enable VXLAN encapsulation between VTEPs

Answer

To ensure loop-free Layer 2 topology

Answer

To reduce the number of VLANs required in the fabric

Question 14

An engineer is configuring vPC on a pair of Nexus switches. Which statement correctly describes the vPC peer-keepalive link?

Accepted Answer

It is a Layer 3 link used to verify the health of the vPC peer. The vPC peer-keepalive link is a Layer 3 link used exclusively to monitor the health of the vPC peer. It sends periodic keepalive messages (typically using UDP port 3200) to detect if the peer switch has failed, enabling the surviving switch to take over the vPC traffic. This link does not carry data traffic, BPDUs, or control-plane information beyond the keepalive probes.

Answer

It is used to forward data traffic between vPC peers

Answer

It must be a dedicated Layer 2 link between vPC peers

Answer

It carries BPDUs to prevent loops

Question 15

In VXLAN overlay networks, which mechanism is used to forward broadcast, unknown unicast, and multicast (BUM) traffic when multicast is not enabled in the underlay?

Accepted Answer

Ingress replication. In VXLAN overlay networks, when multicast is not enabled in the underlay, ingress replication is used to forward BUM traffic. With ingress replication, the source VTEP (ingress node) replicates the BUM packet and sends a separate unicast-encapsulated copy to each remote VTEP in the VXLAN segment. This avoids reliance on underlay multicast trees, making it suitable for networks that do not support multicast routing.

Answer

Head-end replication

Answer

Egress replication

Answer

Multicast replication